An Organic Light-Emitting Diode (OLED) display is one of focuses in the research field of displays at present, and OLED display has lower power consumption, a lower production cost, self-light-emission, a wider angle of view, a higher response speed, and other advantages as compared with a Liquid Crystal Display (LCD). At present, the OLED display has come to take the place of the traditional LCD display in the display fields of a mobile phone, a Personal Digital Assistant (PDA), a digital camera, etc., where the design of a pixel circuit is a core technology in the OLED display, and a research thereon is of great significance.